Pneumatic sand-rammer.



S. OLDHAM.

PNBUMATIG SAND RAMMER.

APPLICATION FILED MAYlG, 1913.

INVENTOR Patented Oct. 7, 1913.

will!! LTS'? wnNEssES ATTORNEYS u'uiTn sTaTns TnTnnT SAMUEL OLDHATJE, 0F PHELABELPHIA, PENNSYLVANA, ASSIGNGR- T@ GEURGE GLD HAM n SON COMPANY, 0F PHILADELPHA, PENNSYLVANIA, .A GRPORATQN- 0F PENNSYLVANIA..

PNEUMATIC SAND-HAMMER,

Specication of Letters Patent.

lliatentedtliettf, 3ft-913';

To al@ 'whom z' may concern:

Be it lrnown that l, Sar/inni, OLDHAM, a citizen ot the United States, residing in the city and county' of Philadelphia, State of Pennsylvania, have invented a new anduscful Pneumatic Sand-Rammer, of which the following is a specification. i

My invention consists ot a pneumatic sandm rammer, Such as is usually employed in ramming molding sand for large castings or *for other molding purposes.

lt further consists of other novel features of construction, all as will be hereinafter fully set forth.

rl`he annexed drawings and the following description set forth in detail one mechanical form embodying the invention, such de tail construction being but one of various mechanical forms in which the principle of the invention may be used.

n said annexed drawings-Figure 1 represents an axial section of my improved pneumatic sand-rammel'. Figs 2 represents an axial section in another plane. Fig. 3 representsl a side elevation of the valve.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings, the reference numeral l indicates a barrel having a cylindrical bore, 2. The lower end of the barrel is formed with an annular shoulder, 3, and with a threaded bore, 4, in the upper end of which is a bevel-faced ring, 5, against which bears 'a packing, (i, compressed by a cap, 7, screwed into the outer end of the bore. ylhe flange, 8, of said cap has recesses, 9, in its upper face, and openings, 10, through it from its lower face and into the bottoms of the recesses. A bore, l1, is formed in the lower end of the barrel and has afbolt, 12,

slidable in it and forced downward by al spring, 13, to engage one of the recesses and thus prevent the cap from turning. A button, 14, closes the upper end of the barrelhore and has a valve-block, l5, bearing against its upper' side, and said block and hut-tonare drawn lagainst, the upper end of the barrel by an internally threaded socket, 16, threaded at its lower end upon the upper threaded end of the barrel. The upper por tion, 17, oi the bore of the socket 1s smooth and of greater diameter than the threaded portion, to form an annular exhaust-chamh'er, which communicates with Jthe atmosphere through one or more exhaust-porta 18. The upper end ot the socket has an inf ternally lthreaded bore, 19for the attach ment of an air-hose or other conduit for compressed air., A piston, 20, is reciprocable in the here of thebarrel, and has a rod, 2l, slidable in the packed gland, and a ramming or tamping head, 22, or other tool is securedV upon the end of said rod, rlhe valve-block hasa valve-chamber, open. atboth ends, and the upper end of said chamber communicates directly with the inlet-bore of the socket. rlhe upper portion, 24.-, of the valve-chamber isof less diameter than the remainder of the chamber and has an annular port-channel, 25, which communicates through a port, 26, with the upper end of a duct, 27, extending downward through the valve-block and the wall of the barrel to near the lower end of the bore of the latter, where it opens into said bore through one or more ports, 28. An intermediate portion 29, of the valve-chamher, of slightly greater diameter than the upper portion, communicates through ports, 30, in the valve-block with theannular enhaust-chamber. A lower portion, 3l, of the valve-chamber is of greater diameter than the intermediate portion and communicates with the live air inlet through a duct, 32, and a port, 33,in the wall of the valve-block. The larger-diameter chamber-portion communicates with the upper portion of the barrel-bore or cylinder by a passage consisting of a port, 34, in the valve-block, a duct,

35, through. the valve block, button, and wall of the barrel, and a port 36, opening into the cylinder a short dista-nce from the upper end of the same. A duct, 37, is formed in the wall of the barrel and communicates at its upper end with the annular exhaustchamber and communicates at its lower end -with the piston-cylinder through. a reliefport, 38, at such distance down in the barrel that it will be uncovered by the piston when the latter approaches the lower` end of its stroke. A duct, 39, is formed in the wall of the barrel and communicates at its upper end with the largerLdia-meter chamber-porn tion through a' rectangularly heut duct, 40, vin the button, and at its lower end with the piston cylinder through a port, 4.1, opposite the relief-port and a port, 4t2, at about the middle ot the length of the cylinder. A valve has play in the valve-chamber and has a large piston, A3 having a sliding .tit in the larger chamher-portionto cover and uncover mit the live-air port and the port in such portion leading into the upper portion of the cylinder. The valve further consists of a reduced neck, 44, and a small piston, 45, having a sliding fit in vthe smaller-diameter chamberportion to move across the annular. portchannel in the'same. The end of the valve has a nose, 46, of smaller diameter than the small piston.

In practice, when air or other pressure fluid is admitted at the air-inlet in the top of the s0cket,being controlled by a suitable valve or other means, not necessary to illustrate, if the parts are in the position illustrated in Fig. 1, the live-air will ass from said inlet through the ports an duct to the lower, large valve-chamber portion, whence it will pass into the cylinder, back of the piston, through the passage 35, driving the piston down. During the reciprocations of the piston, the latter traps suflicient air behind it to cause it to rebound to uncover the port 36, and when first starting the tool, gravity will allow the piston to drop and uncover the port. While the piston is traveling downward, the air below or in front of the piston passes through `the lower distributing port, upward through the duct and into the annular port-channel Ain the upper portion of the valve-chamber,

passing beneath the upper valve-piston and around the stem to the exhaust chamber, whence it escapes to the atmosphere. When the piston in its descent passes the reliefport and uncovers the saine, the pressure below the valve will be relieved, as the pressure back of the piston is reduced, the air below the large valve-piston also escaping through the port 40, duct 39 and port 41 opposite the relief-port, and the live air acting constantly upon the small valve-piston will force'the same downward, closing the live-air inlet to the upper end of the piston-cylinder. When the valve is shifted downward, the small valve-piston uncovers tlie annular port-channel in the small upper valve-chamber portion, and the live air will pass through said channel and the duct leading-,to the lower end of the pistoncylinder, driving the piston upward. The air back of the piston will pass out through the relief-port and its duct into the exhaust chamber, and out into the atmosphere,

- until the.` piston passes and covers such re- A:sa

lief-port, when the air above the piston .will

become compressed. This piston-compressed air will cushion the upstroke of the piston, and as soon as the lowerl'end of the piston uncovers the lower port 42 of the air-distributing duct 39, the live-air will enter said duct and, acting against the larger area of the lower end of the valve, will force the valve upward against the liveair constantly acting a ainst the smaller area of the upper end o the valve. When again be driven down, andthe operation repeated. The reciprocations of the piston will be cushioned at both ends of the Vstroke in the cushion-chambers at both ends of the cylinder, which is desirable in a sand-rammer, as the ramming head is not required to deliver a heavy driving blow, as in a hammer or riveter, but rather a quick succession of tapping blows. The quick reversal of the stroke ofthe piston is insuredb the cushioning of its strokes at both en s, so that the piston may be reversed and'started while the valve is reversed.

The tool is simple of construction and requires a minimum of parts and a minimum of ports and ducts to be drilled. Any form of ramining head may beeinployed, according to the work to be done, the head being preferably detachably secured to the vpistonrod.

Other modes of applying the rinciple of my invention may be employedp for the mode herein explained. Change may therefore be made as regards the mechanism thus disclosed, provided the `principles of construction set forth, respectively, in the following claims are employed.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. In a tool of the character stated, a cylinder having ports at a distance from its ends to form cushion-chambers, a plain cy lindrical piston reciprocable in said cylinder, a valve-chamber at'the upper end of said cylinder having a small-diameter portion having its end open to constant live-air pressure and a closed lar e-diameter portion, and a valve fitted to slide in. said chamber-portions and controlling the air-supply to both ends of the cylinder, said cylinder and valve-chamber havin a duct extending from the bottom of t e large-diameter chamber-portion to a point in the cylinder adapted to be uncovered by the lowers-end of the piston when approachingthe end of its up-stroke to connect the live-air supply inthe lower end of the cylinder with the large-diameter valve-chamber port-ion to raise the valve therein.

2. In a tool of the character stated, a cylinder having a relief port in its upper portion and permanently open to the atmosphere, a plain cylindrical piston recipro# 120'- c able in s aid cylinder, and a valve controlling the air-supply to bbth ends of said cylinder and having a small-area piston exposed to const-ant live-air pressure and anY Lev/5,05?

tion having communication with the cylinder through a port arranged in the latter to be uncovered b the piston when aiproaching the end ofy its up-stroke to a mit the live-air supply in the lower end of the cylinder to said large-area valve-piston to raise the same.

3. `In a tool of the characted stated, a cylinder having a relief port in its upper portion and permanently open to the atmosphere, a piston reciprocable in said cylinder, a valve-chamber formed with a large-diameter portion communicating with the live-air supply and with the upper portion or" the cylinderand also connected at its bottom with the cylinder through a port opposite the relief port and through a port arranged to be uncovered by the piston when approach-ing the end of its up-stroke, lsaid valve chamberl also formed with an intermediate portion having communication with the atmosphere and an upper small-diameter portion constantly open at itsupper end to the live-airl supply and having a port communicating with the lower portion of the cylinder, and a valve having a small-diameter upper piston fitted to slide in the upper chamber-portion to control said latter port, and having its upper face constantly exposed to the llve-air supply and a largediameter lower piston connected to said upper piston by a reduced neck and fitted to slide in the large-diameter chamber-portion to control the live-air port and the port communicating with the upper portion 4of the cylinder.

SAMUEL OLDHAM. Witnesses: l

WM. SECHER, C. D. MGVAY. 

